例子，可以根据按的键盘上的键，显示键盘动作，并显示keyCode值等。
具体操作方法，参照实例中的函数。
<STYLE TYPE="text/css">
TD {text-align:center}
</STYLE>
<SCRIPT LANGUAGE="javascript">
function init() {
document.onkeydown = showKeyDown
document.onkeyup = showKeyUp
document.onkeypress = showKeyPress
}
function showKeyDown(evt) {
evt = (evt) ? evt : window.event
document.getElementById("pressKeyCode").innerHTML = 0
document.getElementById("upKeyCode").innerHTML = 0
document.getElementById("pressCharCode").innerHTML = 0
document.getElementById("upCharCode").innerHTML = 0
restoreModifiers("")
restoreModifiers("Down")
restoreModifiers("Up")
document.getElementById("downKeyCode").innerHTML = evt.keyCode
if (evt.charCode) {
document.getElementById("downCharCode").innerHTML = evt.charCode
}
showModifiers("Down", evt)
}
function showKeyUp(evt) {
evt = (evt) ? evt : window.event
document.getElementById("upKeyCode").innerHTML = evt.keyCode
if (evt.charCode) {
document.getElementById("upCharCode").innerHTML = evt.charCode
}
showModifiers("Up", evt)
return false
}
function showKeyPress(evt) {
evt = (evt) ? evt : window.event
document.getElementById("pressKeyCode").innerHTML = evt.keyCode
if (evt.charCode) {
document.getElementById("pressCharCode").innerHTML = evt.charCode
}
showModifiers("", evt)
return false
}
function showModifiers(ext, evt) {
restoreModifiers(ext)
if (evt.shiftKey) {
document.getElementById("shift" + ext).style.backgroundColor = "#ff0000"
}
if (evt.ctrlKey) {
document.getElementById("ctrl" + ext).style.backgroundColor = "#00ff00"
}
if (evt.altKey) {
document.getElementById("alt" + ext).style.backgroundColor = "#0000ff"
}
}
function restoreModifiers(ext) {
document.getElementById("shift" + ext).style.backgroundColor = "#ffffff"
document.getElementById("ctrl" + ext).style.backgroundColor = "#ffffff"
document.getElementById("alt" + ext).style.backgroundColor = "#ffffff"
}
</SCRIPT>
</HEAD>
<BODY onLoad="init()">
<H1>Keyboard Event Handler Lab</H1>
<HR>
<FORM>
<TABLE BORDER=2 CELLPADDING=2>
<TR><TH></TH><TH>onKeyDown</TH><TH>onKeyPress</TH><TH>onKeyUp</TH></TR>
<TR><TH>Key Codes</TH>
<TD ID="downKeyCode">0</TD>
<TD ID="pressKeyCode">0</TD>
<TD ID="upKeyCode">0</TD>
</TR>
<TR><TH>Char Codes (IE5/Mac; NN6)</TH>
<TD ID="downCharCode">0</TD>
<TD ID="pressCharCode">0</TD>
<TD ID="upCharCode">0</TD>
</TR>
<TR><TH ROWSPAN=3>Modifier Keys</TH>
<TD><SPAN ID="shiftDown">Shift</SPAN></TD>
<TD><SPAN ID="shift">Shift</SPAN></TD>
<TD><SPAN ID="shiftUp">Shift</SPAN></TD>
</TR>
<TR>
<TD><SPAN ID="ctrlDown">Ctrl</SPAN></TD>
<TD><SPAN ID="ctrl">Ctrl</SPAN></TD>
<TD><SPAN ID="ctrlUp">Ctrl</SPAN></TD>
</TR>
<TR>
<TD><SPAN ID="altDown">Alt</SPAN></TD>
<TD><SPAN ID="alt">Alt</SPAN></TD>
<TD><SPAN ID="altUp">Alt</SPAN></TD>
</TR>
</TABLE>
</FORM>
以上通过实例展示了javascript键盘事件的用法，希望对大家有所帮助。